Pneumatic hammer



c. H. PECK PNEUMATI C HAMMER Filed Aug, 5, 1921 5 Sheets-Sheet 1 INVENTOR (aidHPetfi March 10, 1925. 1,528,781 C. H. PECK PNEUMATIC HAMMER Filed Aug, 5, 1.921 3 Sheets-Sheet 2 INVENTOR I COidllPe 01c.

Patented Mar. 10, 1925.

UNITED V STATES 1,528,781 PATENT OFFICE.

CAID H. PECK, F WAVERLY, NEW YORK, ASSIGNOR TO INGERSOLL-RAND COMPANY,

. or JERSEY CITY, NEW JE S .A QOB-lQRA LION or n w JERSEY.

PNEUMATIC HAMMER.

Application filed August 3, 1921. Serial No. 489,516.

To aZZ whom it may concern:

it known that I, Can) H. PEoK, a citizen of the United States, a resident of \Vaverly, county of Tioga, and State of New York, have invented a certain Pneumatic Hammer, of which the following is a specification, accompanied by drawings.

This invention relates to pneumatic tools,

but more particularly to riveting hammers 1c and the like, having a cylinder, a reciprocating piston, which constitutes the hammer and a fluid actuated distributing valve.

The objects of the invention are'to improve upon and increase the efficiency of a is valve .for such pneumatic hammers, sometimes called a central type valve, of hollow cylindrical form, movable in axial alignment with the cylinder preferably in a valve casing located at the rearward end of the cylinder, the valve having a bore equal in diameter to the bore of the cylinder, to

permit the piston to pass through the valve on its rearward stroke.

To these and other ends which will appear, the invention consists of the features of construction, arrangement of parts and combinations of elements substantially as hereinafter fully described and claimed in this specification and shown'in the accom- ::o panying drawings, in which Figure 1 is a diagrammatic longitudinal sectional elevation of a pneumatic hammer embodying the invention, the ports and pass" sages all being shown in one plane for simplicity of illustration and description.

Figure 2 is a similar view ona larger scale, with portions forming no partrof the invention broken away" and the valve shown in its forward position with the piston 40 about to complete its rearward stroke and start on its forward stroke, and

Figure 3 is a similar view with the valve partly in longitudinal section and partly broken away and in its'rearward position with the piston having completed its forward stroke and starting on its rearward stroke.

. Referring to'the drawings, the pneumatic hammer comprises the cylinder A having a bore B in which the pneumatic hammer pistoirC is adapted to reciprocate and impartblows of impact to a rivet set D or other tool removably held within the forward end of the cylinder as by means of the rivet set clip E of any suitable character. A

' valve. intermediate head T having a surface U forming a rearwardly acting intermittently suitable handle F secured to the cylinder as byineans of the bolts G forms the back head of the machine and pressure fluid from the inlet H controlled by the hand operated valve J of any suitable form, is supplied to the machine through the main supply passage K.

In this instance a valve block Land a cap piece 0 fitted together form a valve casing removably held within the rearward end of the cylinder by the handle or back end F.

A. hollow cylindrical fluid actuated differential distribution valve P is slidable longitudinally within the valve casing in axial alignment with the cylinder A and is formed witha bore Q, equal in diameter to the bore of the cylinder, to permit the piston C to pass through the valve on its rearward stroke. The valve P controls the admission and exhaust of motive fluid from both ends of the cylinder by means of suitable ports and passages in the cylinder, the head block L and the cap piece O. The valve is preferably imperforate, having solid walls as shown and all the distributing ports and passages are entirely outside of and external to the valve itself, which enables the valve to be made stronger and of more rugged construction and better able to withstand the hard and continuous usage to which the machine is subjected.

The surface of the rearward end of the valve forms a single forwardly acting pressure area B preferably beveled as shown in the drawings and larger than the pressure surface of the forward beveled end S of the The valve is also provided with an supplied pressure area, and a neck V located forwardly of the head T, for controlling the supply to the forward end of the cylinder through the combined supply and exhaust passage. W in the cylinder, communicating with the forward end of the cylinder through the port X, and also for controlling the exhaust from both ends of the cylinder through the exhaust passage Y preferably protected by a suitable exhaust deflector Z.

Means are provided for holding the valve P in forward position indicated in Figure 2, by live pressure fluid on the larger forwardly acting pressure area B of the valve, as thepiston G travels on its forward stroke, and for this purpose with the parts in the positionv indicated in Figure'2, actuating pressure fluid is admitted from the supply passage K to the groove a in the handle or back head F, thence through thesupply passage 12 in thevalveblockL to the groove, 0 in the valve block and thence to the rearward chamber (Z in the valve block, whichchamber, as shown, is also constantly open to live motive fluid through the small ports t11(l. leading from the main supply. The live pressure fluid which actuates the piston forwardly, actingon'tlie larger'pressure surface R of the valve, will hold the valve in forward position even after the piston in its forward travel has passed the forward end S of the valve, thus subjecting that end of the valve to pressure. fluid. As the piston 0 travels forwardly, the for-. ward end of the cylinder exhausts through theport X, passage V, port 6 in. the cap piece 0, through .the groove f around the valveneck V and through the port g/ to tl le atmosphere through the exhaust passage Means are provided for actuating the valveJP"rearwardly' by live pressure fluidv exerted on the rearwardly acting, intermittently-supplied. pressurezarea- U of the intermediate head T, as the piston completes its forward stroke. Vhen thelpiston has almost delivered its forward or power stroke, thegrearward end of the piston will .haveuncovered a timing portxh in thebore ofthe cylinder communicating ;by means of a passage in the cylinder wall with a timing port A: openinginto the head chamber 0 in the valve block L, in which the. valve head T reciprocates. The cap pieceO is preferably provided 'with a recess'or groove 7) to uncover the timing port 7; and permit said port 7a to be located at the-forward end of the head chamberowhen the block'L andcap piecelOare assembled in,the cylinder. The uncovering of the timing;.port h inthe forwardftravel of the piston admits pressurefluid driving the piston, through passage j and timing port 7a, to the surface U; of the valve head T, which will startthe rearward movement, of the valve.- In order, however, to obtain a quick acting valve, meansareprovided for supplying additional live air pressure to the surface U of thevalve,-and for this purpose a'port g, leading to the head chamber 0, when uncovered by the valve T in its rearward travel,adm its live air pres sure tothe surface U, directly fromthe main supplyb through the passageo'. Any pres sure) in the head chamber 0 behindthe valve head T 'is relieved-through the port s and passages It and a communicating with 'the main eithaust The port sis preferably located a short distance forwardly of the rear end-of the head chamber-in order to trap air and form a cushionbehin'dthe valve head 1 T in its rearward travel.

lVhen the valve has been shifted rearwardly to the position indicated in Figure 3, the piston has delivered its power stroke and pressure fluid for returning the piston is admitted to the forward end of the cylinder from the passage 9 in the valve block L to passage v in the cap piece 0, through the port w in the cap piece, past the neck V of the valve, through the groove f, and thence through the passage W and port X to the forward end of the cylinder for the return stroke. As the piston travels re-arWa-rdly, fluid is exhausted from thecylinder through the-port g and-the exhaust port Y to atmosphere. Pressure against the face U of the valve head T within the head chamber 0 is also released through the timing port 76, passage 7', and timing port 71. when uncovered which communicates with that portion of the cylinder under reduced pressure.

Twotiming ports h and h both communicatingwith the passage j, are preferably provided one forwardly of the other although. one only could be usedif desired. After the rearward end of the piston has passed and covered the exhaust port g, compression of'pressure fluid builds up pressurein the chamber d reaiwardly of the valve P, and the valve is actuated forwardly when suiiicie nt compressionpressure due to live pressure fluid and to compres sion of the fluid by-thepiston rearwardly of the valve acts on the larger rearward pressure areaR of'thevalve, which occurs as the piston-completesits rearward stroke. The valve P then assumes the positionin'dica-ted in Figure 2, and the cycle is repeated. It is evident that with theparts in-the position-indicated in Figure 2, there The cushionformed by pressureafluid trapped'in the chamber (Z in the rearward end of the valve block L, prevents the rear.

ward'end 0f the piston? from strikingthe valve blockenthe returnstroke. Thesinall ports a and 3 w'hich,-as stated, are prefer-- ably provided leading to the chamber (l fromwthe main supplyguinsurethat this chamberis. constantly open. to live air. pressure. Furthermore, if the hammer. is to be used upside down, iforinstance, for. driving rivets, the piston Ciwill drop down against the back end 2 of the valve block L, but'tlie constant airsupply through;- the small- .port X will raise thefvalve P, uncovering the groove 0,

and the live air pressure through the small port 3/ will raise the piston above the face 3, of the chamber d, thus admitting pressure fluid behind the piston into the chamber d for the power stroke.

I claim:

1. A pneumatic hammer comprising a cylinder and piston, a hollow imperforate valve located within the rearward end of the cylinder, through which valve the piston passes, a chamber rearward of the valve constantly open to live pressure fluid, the rearward end of the valve having a forwardly acting pressure area larger than the forward end of the valve, said valve being provided with an intermediate head having a rearwardly acting pressure area, and having a neck located forwardly of said head controlling the supply of pressure fluid to the front end of the cylinder, and the exhaust from both ends of the cylinder, means for holding the valve in forward position by live pressure fluid exerted on the said larger forwardly acting pressure area of the valve, means for intermittently subjecting the said rearwardly acting pressure area of the intern'iediate head to live pressure fluid for actuating the valve rearwardly, and means for actuating the valve forwardly by pressure on the larger forwardly acting pressure area of the valve due to live pres sure fluid and to compression of fluid by the piston in said chamber rearwardly of the valve as the piston completes its rearward stroke.

:2. A pneumatic hammer comprising a cylinder and piston, a hollow imperforate valve located within the rearward end of the cylinder, through which valve the piston passes, a chamber rearward of the valve constantly open to live pressure fluid, the rearward end of the valve having a forwardly acting pressure area larger than the forward end of the valve, said valve being provided with an intermediate head having a rcarwardly acting pressure area, and also having a neck located forwardly of said head controlling the supply of pressure fluid to the front end of the cylinder and the exhaust from both ends of the cylinder, means for holding the valve in forward position by live pressure fluid exerted on the said larger forwardly acting pressure area of the valve, means for intermittently subjecting the said rearwardly acting pressure area of the intermediate head to live pressure fluid from the cylinder to start the valve and to additional live pressure fluid direct from the supply in order to throw the valve more quickly to its rearward position, and means for actuating the valve forwardly by pressure on the larger forwardly acting pressure area of the valve due to live pressure fluid and to compression of fluid by the piston in said chamber rearwardly of the valve as the piston completes its forward stroke.

'3. A pneumatic hammer comprising a cylinder and piston, a solid imperforate valve located within the rearward end of the cylinder, through which valve the piston passes, a chamber rearward of the valve constantly open to live pressure fluid, the rear ward end of the valve havinga forwardly acting pressure area larger than the forward of the said head controlling the supply of motive fluid to the front end of the. cylinder and the exhaust from both ends of the cylinder, means for holding the valve in forward position by live pressure fluid exert-ed on the said larger, forwardly acting pressure area of the valve, means for intermittently subjecting the said rearwardly acting pressure area of said intermediate head to live pressure fluid for actuating the valve rearwardly, and means for actuating the valve forwardly by pressure on the larger for wardly acting pressure area of the valve due to live pressure fluid and to compression of fluid by the piston in said chamber rearwardly of the valve as the piston completes its rearward stroke.

4. A pneumatic hammer comprising a cylinder and piston, a hollow imperforate valve located within the rearward end of the cylinder through which valve the piston passes, a chamber rearward of the valve constantly open to live pressure fluid, the rearward end of the valve having a forwardly acting pressure area larger than the forward end of the valve, said valve being provided with an intermediate head having a rearwardly acting pressure area, and also a surface open to atmosphere for a portion of the forward and rearward travel of the valve but closed to atmosphere for the latter portion of the rearward travel of the valve in order to cushion the valve, said valve also having a neck located forwardly of the said head controlling the supply of motive fluid to the front end of the cylinder and the exhaust from both ends of the cylinder, means for holding the valve in forward position by live pressure fluid exerted on the said larger forwardly acting pressure area of the valve, means for intermittently subjecting the rearwardly acting pressure area of said intermediate head to live pressure fluid from the cylinder to start the valve and to additional live pressure fluid direct from the supply in order to throw the valve more quickly to its rearward position, and means for actuating the valve forwardly by pressure of the larger forwardly acting pressure area of the valve dueto live pressure fluid and to compression of fluid by thepiston: in said chamber rearwardly of the valve as the piston completes its rearward stroke.

5. A pneumatic hammer comprising a cylinder and piston, a hollow imperforate valve e located within the rearward end ofthe cylinder, through which valve the piston passes, a chamber rearward of the valve constantly open to live pressure fluid, the rearward end of the valve having a forwardly acting pressure area larger than the forward end of the valve, said valve being provided with an intermediate head having a rearwardly acting pressure area and a neck located for- Wardly of said head controlling the supply 10 of pressure fluid to the front end ofthe cyl inder and the exhaust from both ends of the cylinder, and admission port at the rear ward end of the cylinder, a head chamber adjacent the valve communicating-with the 5 main supply and with the atmosphere, said intermediate head operating in said head chamber to control said comn'mnication between the head chamber and the supply and the atmosphere, passages controlled by the piston affording communication between the said head chamber and the bore of the cyl inder, means for holding the valve in forward position by live pressure fluid exerted on the said larger forwardly acting pressure area of the valve, the valve being actuated rearwardly as the piston completes its forward stroke, by intermittently subjecting the rearwardly acting pressure area of said intermediate head to live pressure fluid from the'cylinder to start the valve and to additional live pressure fluid direct from the supply in order to throw the valve more quickly to its rearward position, and means for actuating the valve forwardly by pressure on the larger forwardly acting pressure area of the valve due to live pressure fluid and to compression of fluid by the piston in said chamber rearwardly of the valve as the piston completes its rearward stroke.

In testimony whereof I have signed this specification.

CAID H. PECK. 

